The last series of posts focused on punctuation, with the previous post covering slashes, bars, and brackets.

This four part series covers mathematic symbols. It will be fairly limited, since protest posters don’t typically use a wealth of mathematic glyphs. However, it will have more than I originally anticipated, since US protests in early 2017 in defence of science and fact featured a wealth of nerdy math puns.

Part 1 of this series contains the basic math glyphs and their close kin. Made up of mostly horizontal and vertical strokes, this post covers + − ± × ÷ = ≠ and ≈.

### Minus and Other Horizontal Signs

The minus sign (−) is similar to the en dash. Minus is—unhelpfully—sometimes longer, sometimes shorter, and sometimes the same length as the en dash. “How long should this be?” is one of thse questions to which the unfortunate answer is “It depends.” I’m chosing to make mine just a little shorter because… it just seemed right at the time.

Sometimes a designer or artist will just do something because it feels right, and can only explain it later. This is one of those times for me. And I’ll explain it later.

Typically the minus and other mathematic symbols are aligned differently than dashes because they’re meant to work with different glyphs. The dashes are most often used alongside lwercase letters, and are best aligned vertically with respect to the x-height. The math symbols are used with lowercase as well, but also more often with numerals. Since the numerals are much taller, math symbols are a little higher off the baseline so they don’t seems too low compared to numerals.

The equal sign (=) and not equal sign (≠) are just two minuses, one over the other. They should be center aligned vertically to the minus sign, as should most other basic math symbols.

The slash through the not equal sign is usually a lighter weight than the horizontal bars. As far as the length of the slash, well, it depends. It’s not standard; it’s all aesthetics as far as I can tell.

The approximately equal sign (≈) is the same length as the equal and minus signs, but squigly like a tilde. Unlike the tilde, it doesn’t typically have as much variation in weight. A tilde will often be more calligraphic, being thinner at the ends and thicker in the middle. Most times the not equal sign is low contrast or uniform in weight. (Of course there are always exceptions. Franklin Gothic is the opposite, with a high contrast not equal sign and a low contrast tilde.)

### Let’s look at the positives.

The plus sign (+) is a cross with equal sides. Essentially it’s a minus sign with another minus sign rotated 90° at the center. I mentioned above that I did the minus sign a certain size because it felt right. Then I made the plus sign based on the size of the minus. I saw that when aligned with the minus a little above midway to x-height, the top aligns nicely at x-height. So there’s my justification, tenuous as it may be.

The plus minus sign (±) is a minus underneath a shortened plus. The plus is still the same width, but the height is diminished to make room for the minus underneath. It still ends up being taller than a plus, which is not uncommon. The vertical alignment is not quite centered with the minus. It’s just a bit lower because it looks right that way, sitting on the baseline.

The multiplication sign (×) is the same in structure as the plus sign, but it is not just a plus rotated 45°. The height of the multiplication sign should be about the same as the plus. This means the arms are longer, so rotated 45° and placed under the plus, it sticks out each side.

The division sign (÷), is a minus with dots centered horizontally above and below. It’s visually the same height at the plus. Since it has roud forms instead of rectangular forms, the dots have overshoot above and below to appear visually aligned with the plus.

The size of the dots is approximately the same as the dot of the i, which is smaller than the period.

### Up Next

The next post in this series goes over some more comparative symbols, percent, degree, and fraction slash.

• Mathematic Symbols
1. + − ± × ÷ = ≠ ≈
2. > < ≤ ≥ % ° ⁄
3. √ ∫ ∂ ∞
4. ∑ ∏ Δ π
• Diacritics